Transflective liquid crystal device and electronic device using the same

ABSTRACT

A liquid crystal device includes a transparent first substrate with a first transparent electrode formed on the surface thereof, a transparent second substrate with a second transparent electrode is formed thereon, and a liquid crystal layer. A light reflecting layer defining the reflective display region and the transmissive display region is formed on each pixel region. A layer-thickness adjusting layer where a region corresponding to the transmissive display region constitutes an opening, is formed on the upper layer side of the light reflecting layer. In the layer-thickness adjusting layer, the boundary portion of the reflective display region and the transmissive display region constitutes an inclined surface, and a light shielding film is two-dimensionally superimposed on this boundary region.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.10/775,893 filed Feb. 10, 2004, which is a divisional of U.S. patentapplication Ser. No. 10/255,145 filed Sep. 25, 2002 which claimspriority to Japanese Patent Application Nos. 2002-227,828, filed Aug. 5,2002, 2002-005250 filed Jan. 11, 2002 and 2001-292-644 filed Sep. 25,2001. The above applications are hereby incorporated by reference hereinin their entireties.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to a transflective liquid crystal device.More particularly, the present invention relates to a multi-gap typeliquid crystal device in which the layer thickness of a liquid crystallayer between a transmissive display region and a reflective displayregion within a single pixel, has been changed into an appropriatevalue.

2. Description of the Related Art

Among a variety of liquid crystal devices, ones that are capable ofdisplaying images both in a transmissive mode and in a reflective modeare referred to as “transflective liquid crystal devices”, and are usedin all scenes.

As shown in FIGS. 21A to 21C, the transflective liquid crystal devicecomprises a transparent first substrate 10 with first transparentelectrodes 11 formed on the surface thereof, a transparent secondsubstrate 20 with second transparent electrodes 21 formed on its surfaceside opposed to the first electrodes 11, and a TN (Twisted Nematic) modeliquid crystal layer 5 held between the first substrate 10 and thesecond substrate 20. On the first substrate 10, light reflecting layers4 each constituting a reflective display region 31 is formed in one ofpixel regions 3 where the first transparent electrodes 11 and the secondtransparent electrodes 21 are opposed. The remaining regions where thelight reflecting layers 4 are not formed, each constitutes atransmissive display region 32. Polarizers 41 and 42 are disposed on theouter surfaces of the first and second substrates 10 and 20,respectively. A backlight device 7 is opposed to the polarizer 41 side.

In the liquid crystal device 1 with this arrangement, out of lightemitted from the backlight device 7, the light made incident on thetransmissive display region 32 enters the liquid crystal layer 5 fromthe first substrate 10 side, as indicated by the arrow L1. After havingbeen subjected to an optical modulation at the liquid crystal layer 5,the light is emitted from the second substrate 20 side as transparentdisplay light, thereby displaying an image (transmissive mode).

Also, out of external light made incident from the second substrate 20side, the light entering the reflective display region 31 reaches thereflective layer 4 through the liquid crystal layer 5, as indicated bythe arrow 2. After having been reflected from the reflective layer 4,the light again passes through the liquid crystal layer 5, and isemitted from the second substrate 20 side as a reflective display light,thereby displaying an image (reflective mode).

On the first substrate 10, a reflective display color filter 81 and atransmissive display color filter 82 are formed in each of thereflective display regions 31 and each of the transmissive regions 32,respectively, thereby allowing color display.

When performing such an optical modulation, if the twisted angle of aliquid crystal is set to be small, the change in a polarizationcondition becomes a function of the product of a difference in therefractive index Δn and a layer thickness d of the liquid crystal layer5, i.e., the retardation Δn·d. Therefore, making this value anappropriate one allows the achievement of the display giving highvisibility. However, in the transflective liquid crystal device 1, thetransmissive display light only once passes through the liquid crystallayer 5 and is emitted, whereas the reflective display light twicepasses through the liquid crystal layer 5, and therefore, it isdifficult to optimize the retardation Δn·d for both the transmissivedisplay light and the reflective display light. Hence, if the layerthickness d of the liquid crystal layer 5 is set so that the display ina reflective mode has high visibility, the display in a transmissivemode will be sacrificed. Conversely, if the layer thickness d of theliquid crystal layer 5 is set so that the display in a transmissive modehas high visibility, the display in a reflective mode will besacrificed.

Accordingly, Japanese Unexamined Patent Application Publication No.11-242226 discloses a configuration in which the layer thickness d ofthe liquid crystal layer 5 in the reflective display region 31 is lessthan that of the liquid crystal layer 5 in the transmissive displayregion 32. Such a configuration is referred to as a “multi-gap type”.For example, as shown in FIGS. 21A to 21C, this type of configurationcan be implemented by a layer-thickness adjusting layer 6 in which aregion corresponding to the transmissive display region 32 constitutesan opening, on the lower layer side of the first transparent electrode11, and on the upper layer side of the light reflecting layer 4. Morespecifically, in the transmissive display region 32, the layer thicknessd of the liquid crystal layer 5 is larger than in the reflective displayregion 31 by the layer thickness of the layer-thickness adjusting layer6, and hence, it is possible to optimize the retardation Δn·d for boththe transmissive display light and the reflective display light. Herein,in order to adjust the layer thickness d of the liquid crystal layer 5by the layer-thickness adjusting layer 6, it is necessary to thicklyform the layer-thickness adjusting layer 6. A photoresist or the like isused to form such a thick layer.

While a photolithography technique is used when the layer-thicknessadjusting layer 6 is formed with a photoresist, the layer-thicknessadjusting layer 6 becomes an upwardly inclined surface 60 in theboundary region of the reflective display region 31 and the transmissivedisplay region 32, due to problems such as the exposure accuracy whenperforming the photolithography, the side etching during development. Asa result, in the boundary portion of the reflective display region 31and the transmissive display region 32, the layer thickness d of theliquid crystal layer 5 continuously varies, so that the retardation Δn·dcontinuously varies, as well. As for the liquid crystal moleculescontained in the liquid crystal layer 5, the initial alignment conditionis defined by alignment films 12 and 22 formed on the outermost layersof the first and second substrates 10 and 20, respectively. However, onthe inclined surface 60, since the alignment regulating force on thealignment film 12 acts in an oblique direction, the alignment of theliquid crystal molecules in this portion is disturbed.

Even if the above-described boundary portion does not constitute aninclined surface, there is the possibility that the substrate and astepped portion orthogonally intersect each other, thereby disturbingthe alignment of the liquid crystal molecules.

As a consequence, in the conventional liquid crystal device 1, when itis designed, for example, as a normally white type, although the fullscreen must become black display with an electric field applied, lightleaks from the portion corresponding to the inclined surface 60, therebycausing a display failure such as a reduction in the contrast.

To solve the above-described problems, the object of the presentinvention is to provide an arrangement capable of performinghigh-quality display even if the retardation is in an inappropriatecondition, or the alignment of liquid crystal molecules is in adisturbed condition in the boundary portion of the transmissive displayregion and the reflective display region, in a multi-gap type liquidcrystal device in which the layer thickness of the liquid crystal layerbetween the transmissive display region and the reflective displayregion within a single pixel has been changed into an appropriate value,and in an electronic device using the same.

SUMMARY OF THE INVENTION

In order to solve the above-described problems, the present inventionprovides a transflective liquid crystal device that comprises a firstsubstrate with a first transparent electrodes formed on the surfacethereof; a second substrate with second transparent electrodes formed onits surface side opposed to the first electrodes; and a liquid crystallayer held between the first and second substrates. The first substrateincludes light reflecting layers each of which constitutes a reflectivedisplay region in one of pixel regions where the first transparentelectrodes and the second transparent electrode are mutually opposed andeach of which defines the remaining region of each of the pixel regionsas a transmissive display region, layer-thickness adjusting layers eachmaking it possible for the layer thickness of the liquid crystal layerin the reflective display region to be less than the layer thickness ofthe liquid crystal layer in the transmissive display region, and thefirst transparent electrodes, in a manner such as to be stacked in thisorder from the lower layer side to the upper layer side. Herein, on atleast one of the first and second substrates, a light shielding film isformed so as to be superimposed on the boundary region of the reflectivedisplay region and the transmissive display region.

Also, the present invention provides a transflective liquid crystaldevice having reflective display regions and transmissive displayregions. This transflective liquid crystal device comprises a firstsubstrate; a second substrate with second transparent electrodes formedon its surface side opposed to the first electrodes; and a liquidcrystal layer held between the first and second substrates. The firstsubstrate includes, in the reflective display region, a layer-thicknessadjusting layer making it possible for the layer thickness of the liquidcrystal layer in the reflective display region to be less than the layerthickness of the liquid crystal layer in the transmissive displayregion, and a light reflecting electrode, in a manner such as to bestacked in this order from the lower layer side to the upper layer side.The first substrate also has a transparent electrode on each of thetransmissive display regions. Herein, on at least one of the first andsecond substrates, a light shielding film is formed so as to besuperimposed on the boundary region of the reflective display region andthe transmissive display region.

Furthermore, the present invention provides a transflective liquidcrystal device that comprises a first substrate with first transparentelectrodes formed on the surface thereof; a second substrate with asecond transparent electrodes formed on its surface side opposed to thefirst electrodes; and a liquid crystal layer held between the first andsecond substrates. The first substrate includes light reflecting layerseach of which constitutes a reflective display region in one of pixelregions where the first transparent electrodes and the secondtransparent electrodes are mutually opposed and each of which definesthe remaining region of each the pixel regions as a transmissive displayregion, and the first transparent electrodes, in a manner such as to bestacked in this order from the lower layer side to the upper layer side.The second substrate includes, in the reflective display region, alayer-thickness adjusting layer making it possible for the layerthickness of the liquid crystal layer in the reflective display regionto be less than the layer thickness of the liquid crystal layer in thetransmissive display region, and the second transparent electrodes, in amanner such as to be stacked in this order from the lower layer side tothe upper layer side. Herein, on at least one of the first and thesecond substrates, a light shielding film is formed so as to besuperimposed on the boundary region of the reflective display region andthe transmissive display region.

Moreover, the present invention provides a transflective liquid crystaldevice having reflective display regions and transmissive displayregions. This transflective liquid crystal device comprises a firstsubstrate; a second substrate with second transparent electrodes formedon its surface side opposed to the first electrodes; and a liquidcrystal layer held between the first and the second substrates. Thefirst substrate has a light reflecting electrode formed on each of thereflective display regions, and a transparent electrode formed on eachof the transmission region. The second substrate includeslayer-thickness adjusting layers each making it possible for the layerthickness of the liquid crystal layer in the reflective display regionto be less than the later thickness of the liquid crystal layer in thetransmissive display region, and the transparent electrodes, in a mannersuch as to be stacked in this order from the lower layer side to theupper layer side. Herein, on at least one of the first and secondsubstrates, a light shielding film is formed so as to be superimposed onthe boundary region of the reflective display region and thetransmissive display region.

In the present invention, the boundary region of the reflective displayregion and the transmissive display region refers to the regioncomprising the boundary of the reflective display region and thetransmissive display region defined by the edge of the light reflectinglayer or a light reflecting electrode, and the edge portion of thereflective display region adjacent to this boundary and/or the edgeportion of the transmissive display region adjacent to this boundary.

In the present invention, light shielding films are each formed so as tobe superimposed on the boundary region of the reflective display regionand the transmissive display region. As a result, even when thethickness of each of the layer-thickness adjusting layers continuouslyvaries, and consequently the retardation Δn·d continuously varies inthis portion, or the alignment of liquid crystal molecules is disturbed,neither reflective display light nor transmissive display light would beemitted from such a region.

This prevents a malfunction such as a light leakage during blackdisplay, thus making it possible to provide high-contrast andhigh-quality display.

In the present invention, the light shielding film is formed, forexample, on the first transparent substrate side. Alternatively, thelight shielding film may be formed on the second transparent substrateside.

In the present invention, it is preferable that the layer-thicknessadjusting layer be arranged so that the boundary region of thereflective display region and the transmissive display regionconstitutes an inclined surface.

In the present invention, it is preferable that the light shielding filmbe formed in the region in which the light shielding film istwo-dimensionally superimposed on the inclined surface of thelayer-thickness adjusting layer.

Here, that the light shielding film is formed in the region in which thelight shielding film is two-dimensionally superimposed on the inclinedsurface, means that the inclined surface and the light shielding filmare superimposed on each other in a plan view. Namely, the inclinesurface may be included in the light shielding film.

In the present invention, it is preferable that the light shielding filmbe formed so as to be two-dimensionally superimposed on the edge portionof the light reflecting layer. In this invention, the design is made sothat the boundary region of the reflective display region and thetransmissive display region is covered with the light shielding film.However, there is the possibility that, due to error in the formation ofthe light reflecting film and/or the error in the formation of the lightshielding film, light leak from the boundary region of the reflectivedisplay region and the transmissive display region, that is, from theboundary region of the region where the light reflecting layer or thelight reflecting electrode is formed and the remaining region, and thatthe leakage light transmits through portions where the layer-thicknessadjusting layer varied in the thickness and/or portions where thealignment of liquid crystal molecules is disturbed, and is emitted,thereby causing malfunctions such as a reduction in the contrast.Accordingly, forming a light shielding film so as to betwo-dimensionally superimposed on the edge portion of the lightreflecting layer or the light reflecting electrode, allows the lightleakage from the boundary region of the reflective display region andthe transmissive display region to be reliably inhibited.

In the present invention, the transmissive display region is disposed,for example, in an insular shape within the reflective display region.

In the present invention, the transmissive display region may bedisposed at the end portion of the pixel region.

In the present invention, when the pixel region is formed as arectangular region, it is preferable that the transmissive displayregion have, for example, a rectangular shape at least one side of whichis superimposed on a side of the pixel region. As the forming region ofthe light shielding film becomes wider, the quantity of light, whichcontributes to display, decreases, and thereby the display becomesdarker. However, by superimposing a side of the transmissive displayregion on a side of the pixel region, the total length of the boundaryregion of the transmissive display region and the reflective displayregion, that is, the total length of the light shielding layer can becorrespondingly reduced. Consequently, because the total length of thelight shielding film 9 is short, the reduction in the amount of lightcontributed to the display can accordingly kept to a minimum. In thiscase, since light shielding films 90 and the light shielding wiringlines are, generally speaking, formed in the boundary regions ofadjacent pixel regions 3, the parts of the periphery of the transmissivedisplay region 32 that are covered by these light shielding films 90 donot of course contribute to display. Hence, even if there aredisturbances in the retardation or in the alignments of liquid crystalat these portions, the deterioration of the quality of the display canbe prevented.

As such a configuration, for example, the transmissive display regionmay have any one of a configuration in which the transmissive displayregion is positioned so that one side thereof is superimposed on a sideof the pixel region, a configuration in which the transmissive displayregion is positioned so that two sides thereof are superimposed on sidesof the pixel region, and a configuration in which the transmissivedisplay region is positioned so that three sides thereof aresuperimposed on sides of the pixel region. Herein, when a lightshielding wiring line runs as the light shielding film so as to dividethe pixel region into two, and the reflective display region and thetransmissive display region are disposed on respective opposite sides ofthe wiring line, a configuration in which the transmissive displayregion is positioned so that three sides thereof are superimposed onsides of the pixel region, is implemented.

In the present invention, when the reflective display regions and thetransmissive display region are individually provided with a colorfilter, a transflective liquid crystal device for color display can beconstituted. In this case, it is preferable that a reflective displaycolor filter be formed in each of the reflective display regions, whilea transmissive display color filter having a coloring degree higher thanthat of the reflective display color filter, be formed in each of thetransmissive display regions.

In the present invention, the arrangement may be any one of aconfiguration in which the reflective display region is wider than thetransmissive display region, a configuration in which the reflectivedisplay region is narrower than the transmissive display region, and aconfiguration in which the reflective display region and thetransmissive display region are equal in area.

The liquid crystal device to which the present invention is applied, canbe used as a display device for electronic devices such as portabletelephones, mobile computers, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1C are schematic views showing a single pixel region of aplurality of pixel regions formed into a matrix shape in a transflectiveliquid crystal device according to a first embodiment of the presentinvention, where FIG. 1A is a plan view thereof, and FIGS. 1B and 1C arerepresentations of the A-A′ section and the B-B′ section thereof,respectively.

FIGS. 2A to 2C are schematic views showing a single pixel region of aplurality of pixel regions formed into a matrix shape in a transflectiveliquid crystal device according to a second embodiment of the presentinvention, where FIG. 2A is a plan view thereof, and FIGS. 2B and 2C arerepresentations of the A-A′ section and the B-B′ section thereof,respectively.

FIGS. 3A to 3C are schematic views showing a single-pixel region of aplurality of pixel regions formed into a matrix shape in a transflectiveliquid crystal device according to a third embodiment of the presentinvention, where FIG. 3A is a plan view thereof, and FIGS. 3B and 3C arerepresentations of the A-A′ section and the B-B′ section thereof,respectively.

FIGS. 4A and 4B are schematic views showing a single pixel region of aplurality of pixel regions formed into a matrix shape in a transflectiveliquid crystal device according to a fourth embodiment of the presentinvention, where FIG. 4A is a plan view thereof, and FIG. 4B is arepresentation of the B-B′ section thereof.

FIG. 5 is a sectional view showing a plurality of pixel regions formedinto a matrix shape in a transflective liquid crystal device accordingto a fifth embodiment of the present invention, this sectional viewcorresponding to FIG. 1B.

FIG. 6 is a sectional view showing a plurality of pixel regions formedinto a matrix shape in a transflective liquid crystal device accordingto a sixth embodiment of the present invention, this sectional viewcorresponding to FIG. 1B.

FIG. 7 is a sectional view showing a plurality of pixel regions formedinto a matrix shape in a transflective liquid crystal device accordingto a seventh embodiment of the present invention, this sectional viewcorresponding to FIG. 1B.

FIG. 8 is a sectional view showing a plurality of pixel regions formedinto a matrix shape in a transflective liquid crystal device accordingto an eighth embodiment of the present invention, this sectional viewcorresponding to FIG. 1B.

FIG. 9 is a block diagram schematically showing the electricalconstruction of a transflective TFD active matrix type liquid crystaldevice according to a ninth embodiment of the present invention.

FIG. 10 is a schematic exploded view illustrating the structure of theliquid crystal device shown in FIG. 9.

FIG. 11 is a plan view corresponding to a single pixel on an elementsubstrate out of a pair of substrates sandwiching the liquid crystaltherebetween in the liquid crystal device shown in FIG. 10.

FIG. 12A is a sectional view taken along the line III-III′ in FIG. 11,and FIG. 12B is a perspective view illustrating the TFD element shown inFIG. 11.

FIG. 13 is a plan view showing a transflective TFT active matrix typeliquid crystal device according to a tenth embodiment of the presentinvention, as seen from the side of an opposed substrate.

FIG. 14 is a sectional view taken along the line H-H′ in FIG. 13.

FIG. 15 is an equivalent circuit diagram of various elements and wiringlines formed on a plurality of pixels arranged in a matrix shape in theliquid crystal device shown in FIG. 13.

FIG. 16A is a plan view illustrating the configurations of pixels formedon a TFT array substrate to which the arrangement according to any oneof the embodiments 1 to 3, or 5 to 8 has been applied, in the liquidcrystal device shown in FIG. 13, and FIG. 16B is a plan viewillustrating the configurations of pixels formed on a TFT arraysubstrate to which the arrangement according to the embodiment 4 hasbeen applied.

FIG. 17 is a sectional view showing some of the pixels of the liquidcrystal device shown in FIG. 13, the sectional view being obtained bycutting them at the position corresponding to the line C-C′ shown inFIGS. 16A and 16B.

FIG. 18 is a block diagram showing the circuit configuration of anelectronic device in which a liquid crystal device according to thepresent invention is used as a display.

FIG. 19 is a representation of a mobile personal computer as anembodiment of an electronic device using a liquid crystal deviceaccording to the present invention.

FIG. 20 is a representation of a portable telephone as an embodiment ofan electronic device using a liquid crystal device according to thepresent invention.

FIGS. 21A to 21C are schematic views showing a single pixel region of aplurality of pixel regions formed into a matrix shape in a relatedtransflective liquid crystal device, where FIG. 21A is a plan view, andFIGS. 21B and 21C are representations of the A-A′ section and the B-B′section thereof, respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments of the present invention will be described withreference to the drawings. In the drawings used for descriptions below,in order to make the dimensions of layers and members recognizable ondrawings, different scales are used for each layer and every member.

First Embodiment

FIGS. 1 a to 1 c are schematic views showing a single pixel region of aplurality of pixel regions formed into a matrix shape in a liquidcrystal device, where FIG. 1 a is a plan view thereof, and FIGS. 1 b and1 c are representations of the a-a′ section and the b-b′ sectionthereof, respectively. Since the liquid crystal device according to thisembodiment has the same basic structure as in conventional liquidcrystal devices, portions having the same functions are designated bythe same reference numerals.

The pixel region shown in FIGS. 1A to 1C shows the portion of an activematrix type liquid crystal device to be described later that is commonto cases where either TFDs or TFTs are used as non-linear elements forpixel switching. The liquid crystal device 1 illustrated here comprisesa transparent first substrate 10 which is constituted of quartz orglass, and on the surface of which first transparent electrodes 11 eachconstituted of an ITO (Indium Tin Oxide) film or the like are formed; atransparent second substrate 20 which is constituted of quartz or glass,and on which second transparent electrodes each constituted of an ITOfilm or the like are formed on its surface side opposed to the firstelectrodes 11; a liquid crystal layer 50 including a TN mode liquidcrystal held between the first substrate 10 and the second substrate 20.The regions where the first transparent electrodes 11 and the secondtransparent electrodes 21 are mutually opposed constitute the pixelregions 3, which directly contribute to display.

In the liquid crystal device 1, numbers of pixel regions 3 are formedinto a matrix shape, and when the boundary regions of these pixelregions 3 are two-dimensionally viewed, light shielding films 90referred to as “black matrixes” or “black stripes” formed on the firstsubstrate 10 or second substrate 20, or light shielding wiring lines(not shown) run through the boundary regions. The pixel regions 3,therefore, are each in a state surrounded by the light shielding films90 or light shielding wiring lines in a plan view.

On the first substrate 10, rectangular light reflecting layers 4 eachconstituting a reflective display region 31 are each constituted of analuminum film or a silver alloy film, in the rectangular pixel region 3where the first transparent electrode 11 and the second transparentelectrode 21 are mutually opposed, and a rectangular opening 40 isformed at the center of each of the light reflecting layers 4. As aresult, in each of the pixel regions 3, the region where the lightreflecting layer 4 is formed constitutes the reflective display region31, while the region corresponding to the opening 40 constitutes aninsular and rectangular transmissive display region 32 where the lightreflecting layer 4 is not formed.

Polarizers 41 and 42 are disposed on the outer surfaces of the first andsecond substrate 10 and 20, respectively, and a backlight device 7 isopposed to the polarizer 41 side.

In the liquid crystal device 1 with this arrangement, out of lightemitted from the backlight device 7, the light that has fallen on thetransmissive display region 32 enters the liquid crystal layer 50 fromthe first substrate 10 side, as indicated by the arrow L1. After havingbeen subjected to an optical modulation at the liquid crystal layer 50,the light is emitted from the second substrate 20 side as transparentdisplay light, thereby displaying an image (transmissive mode).

Also, out of external light entering from the second substrate 20 side,the light entering the reflective display region 31 reaches thereflective layer 4 through the liquid crystal layer 50, as indicated bythe arrow L2. After having been reflected from the reflective layer 4,the light again passes through the liquid crystal layer 50, and isemitted from the second substrate 20 side as a reflective display light,thereby displaying an image (reflective mode).

Here, on the first substrate 10, a reflective display color filter 81and a transmissive display color filter 82 are formed in each of thereflective display regions 31 and each of the transmissive regions 32,respectively, thereby allowing color display. As a transmissive displaycolor filter 82, a filter having a coloring degree higher than that ofthe reflective display color filter 81, such as a filter in which alarge quantity of pigments are contained, is employed.

In such a transflective liquid crystal device 1, the transmissivedisplay light only once passes through the liquid crystal layer 50 andis emitted, whereas the reflective display light twice passes throughthe liquid crystal layer 50. Accordingly, in the first substrate 10, onthe lower layer side of the first transparent electrode 11, and on theupper layer side of the light reflecting layer 4, layer-thicknessadjusting layers 6 each of which comprises a photoresist and in which aregion corresponding to the transmissive display region 32 constitutesan opening 61 is formed. Therefore, in the transmissive display region32, since the layer thickness d of the liquid crystal layer 50 is largerthan in the reflective display region 31 by the layer thickness of thelayer-thickness adjusting layer 6, it is possible to optimize theretardation Δn·d for both the transmissive display light and thereflective display light.

While a photolithography technique is used when the layer-thicknessadjusting layer 6 is formed, the layer-thickness adjusting layer 6constitutes an upwardly inclined surface 60 in the boundary region ofthe reflective display region 31 and the transmissive display region 32,due to problems such as the exposure accuracy when performing thephotolithography, and the side etching during development. Specifically,this inclined surface 60 is formed so as to have a width of 8 μm in aplan view. As a result, in the boundary portion of the reflectivedisplay region 31 and the transmissive display region 32, the layerthickness d of the liquid crystal layer 50 continuously varies, so thatthe retardation Δn·d continuously varies, as well. As for the liquidcrystal molecules contained in the liquid crystal layer 50, the initialalignment condition is defined by alignment films 12 and 22 formed onthe outermost layer of the first and second substrates 10 and 20,respectively. However, on the inclined surface 60, since the aligningforce of the alignment film 12 acts in an oblique direction, thealignment of the liquid crystal molecules in this portion is disturbed.

The boundary region in such an unstable state causes the degradation ofthe quality of display, and therefore, in this embodiment, on the firstsubstrate 10, light shielding films 9 are each formed so as to besuperimposed over the entire boundary region of the reflective displayregion 31 and the transmissive display region 32. Also, each of thelight shielding films 9 is formed so as to have a width of about 9 μmand so that the inclined surface thereof 60 is included in the lightshielding film 9 in a plan view. More specifically, in this embodiment,the light shielding film 9 constituted of a light shielding metallicfilm such as a chrome film, is formed into a rectangular frame shapealong the entire inner peripheral edge of the light reflecting layer 4,which separates the reflective display region 31 and the transmissivedisplay region 32, in a manner such that one portion of the lightshielding film 9 covers the edge portion of the light reflecting layer4.

In this manner, in the present embodiment, each of the light shieldingfilms 9 is formed so as to be superimposed over the entire boundaryregion of the reflective display region 31 and the transmissive displayregion 32. As a result, even when the thickness of each of thelayer-thickness adjusting layers 6 continuously varies in the boundaryregion of the reflective display region 31 and the transmissive displayregion 32, and consequently the retardation Δn·d continuously varies inthis portion, or the alignment of liquid crystal molecules is disturbed,neither reflective display light nor transmissive display light would beemitted from such a region. Also, since each of the light shieldingfilms 9 is formed so as to be two-dimensionally superimposed on theinner peripheral edge of the light reflecting layer 4, there is no riskof light leakage occurring in the boundary region of the reflectivedisplay region 31 and the transmissive display region 32. This preventsa malfunction such as a light leakage during black display, thus makingit possible to provide high-contrast and high-quality display.

As a transmissive display color filter 82, a filter having a coloringdegree higher than that of a reflective display color filter 81 is used.As a result, even in an arrangement in which the transmissive displaylight passes through the color filter only once, the display issubjected to coloring equivalent to that of the reflective displaylight, which twice passes through the color filter, thereby allowing theachievement of a high quality color display.

When producing the liquid crystal device 1 with such a structure, thefirst substrate 10 is formed as follows.

First, a first substrate 10 comprising quartz or glass is prepared, anda reflective metallic film such as aluminum or silver alloy is formedover the entire surface thereof. Then, the photolithography technique isused to pattern this metallic film to form light reflecting layers 4.When attempting to provide the first substrate with a scatteringfunction, a scattering structure may be formed by glass etching or byusing resin before forming the metallic film.

Next, a light shielding metallic film such as chrome is formed over theentire surface of the first substrate 10, and then the photolithographytechnique is used to pattern this metallic film to form the lightshielding films 9.

Then, a flexo printing method, the photolithography technique, or an inkjet printing method is used to form the reflective display color filters81 and the transmissive display color filters 82 on respectivepredetermined regions.

Thereafter, a spin coat method is used to apply a photoresist over theentire surface of the first substrate 10, and then the layer-thicknessadjusting layers 6 are formed by exposure and development processes.

Next, a transparent conductive film such as an ITO film is formed overthe entire surface of the first substrate 10, and then thephotolithography technique is used for patterning this transparentconductive film to form the first transparent electrodes 11.

Then, the spin coat method is used to apply polyimide resin over theentire surface of the first substrate 10, and after conducting a bakingtreatment, an alignment film 12 is formed by performing an aligningtreatment such as a rubbing treatment.

The first substrate 10 formed in this way is bonded to the secondsubstrate 20 that has been formed separately, with a predetermineddistance therebetween, and then a liquid crystal is injected between thesubstrates to form the liquid crystal layer 50.

In the liquid crystal device 1, non-linear elements for pixel switching,such as TFDs or TFTs, may be formed on the first substrate 1 side. Insuch cases, the light shielding films 9 and other layers may be formedby making use of a portion of the process of forming the TFDs or theTFTs.

As for the arrangement comprising the reflective display region 31 andtransmissive display region 32, any structure may be selected out of astructure in which the reflective display region 31 is wider than thetransmissive display region 32, a structure in which the reflectivedisplay region 31 is narrower than the transmissive display region 32,and a structure in which the reflective display region 31 and thetransmissive display region 32 are equal in area.

Second Embodiment

FIGS. 2A to 2C are schematic views showing a single pixel region of aplurality of pixel regions formed into a matrix shape in a liquidcrystal device of this embodiment, where FIG. 2A is a plan view thereof,and FIGS. 2B and 2C are representations of the A-A′ section and the B-B′section thereof, respectively. Since the liquid crystal devicesaccording to this embodiment and third to eighth embodiments has thesame basic structure as in the first embodiment, portions with the samefunctions are designated by the same reference numerals, withoutdetailed description. The producing method for this embodiment is alsothe same as that for the first embodiment, and the explanation thereofis omitted.

As in the case of the first embodiment, the pixel region shown in FIGS.2A to 2C shows the portion of an active matrix type liquid crystaldevice that is common to cases where either TFDs or TFTs are used asnon-linear elements for pixel switching. The liquid crystal device 1illustrated here also comprises a transparent first substrate 10 withfirst transparent electrodes 11 formed on the surface thereof; atransparent second substrate 20 with second transparent electrodesformed on its surface side opposed to the first electrodes 11; and aliquid crystal layer 50 including a TN mode liquid crystal held betweenthe first substrate 10 and the second substrate 20. The regions wherethe first transparent electrodes 11 and the second transparentelectrodes 21 are mutually opposed constitute the pixel regions 3, whichdirectly contribute to display. The pixel regions 3 are each in a statesurrounded by the light shielding films 90 or light shielding wiringlines in a plan view.

On the first substrate 10, light reflecting layers 4 each constitutingreflective display region 31 are each formed of an aluminum film or asilver alloy film, in the rectangular pixel region 3 where the firsttransparent electrode 11 and the second transparent electrode 21 aremutually opposed, and a rectangular opening 40 is formed at the portioncorresponding to one side of each of the light reflecting layers 4. As aresult, in each of the pixel regions 3, the region where the lightreflecting layer 4 is formed constitutes the reflective display region31, while the region corresponding to the opening 40 constitutes arectangular transmissive display region 32 where the light reflectinglayer 4 is not formed. Here, one side of the transmissive display region32 is superimposed on one side of the pixel region 3.

Polarizers 41 and 42 are disposed on the outer surfaces of the first andsecond substrate 10 and 20, respectively, and a backlight device 7 isopposed to the polarizer 41 side. Also, on the first substrate 10, areflective display color filter 81 and a transmissive display colorfilter 82 are formed in each of the reflective display regions 31 andeach of the transmissive display regions 32, respectively, therebyallowing color display.

In this embodiment also, in the first substrate 10, on the lower layerside of the first transparent electrode 11, and on the upper layer sideof the light reflecting layer 4, there are provided layer-thicknessadjusting layers 6 each of which comprises a photoresist and in each ofwhich a region corresponding to the transmissive display region 32constitutes an opening 61. Therefore, in the transmissive display region32, since the layer thickness d of the liquid crystal layer 5 is largerthan in the reflective display region 31 by the layer thickness of thelayer-thickness adjusting layer 6, the retardation Δn·d is optimized forboth the transmissive display light and the reflective display light.

In each of the layer-thickness adjusting layers 6, an upwardly inclinedsurface 60 is formed in the boundary region of the reflective displayregion 31 and the transmissive display region 32 so as to have a widthof 8 μm. Accordingly, in this embodiment, on the first substrate 10,light shielding films 9 are each formed in a U-shape in a plan view soas to be superimposed over the entire boundary region of the reflectivedisplay region 31 and the transmissive display region 32. Each of thelight shielding film 9 has a width of 9 μm, and is formed so that theinclined surface 60 is included in the light shielding film 9 in a planview. More specifically, in this embodiment, each of the light shieldingfilms 9 comprising a light shielding metallic film such as a chromefilm, is formed into a U-shape along the three sides except the regionthat is superimposed on one side of the pixel region 3, out of the foursides of the rectangular transmissive display region 32, in a mannersuch that one portion of the light shielding film 9 covers the edgeportion of the light reflecting layer 4.

Accordingly, in this embodiment, since each of the light shielding films9 is formed so as to be superimposed over the entire boundary region ofthe reflective display region 31 and the transmissive display region 32as in the case of the first embodiment, it is possible to prevent amalfunction such as a light leakage in the boundary region of thereflective display region 31 and the transmissive display region 32,during black display. Thus, this embodiment produces the same effect asthat of the first embodiment.

As the forming region of the light shielding film 9 becomes wider, thequantity of light, which contributes to display, decreases, and thedisplay tends to be darker. However, in this embodiment, the lightshielding film 9 is formed in a U-shape in a plan view, and the lightshielding film 9 is not formed at the portion corresponding to one sideof the transmissive display region 32. Consequently, because the totallength of the light shielding film 9 is short, the reduction in theamount of light contributed to the display can accordingly be kept to aminimum. In this case, since light shielding film 90 and light shieldingwiring lines are, generally speaking, formed in the boundary regions ofadjacent pixel regions 3, the parts of the periphery of the transmissivedisplay region 32 that are covered by these light shielding films 90 donot of course contribute to display. Hence, even if there aredisturbances in the retardation or in the alignment of liquid crystal inthese portions, the deterioration of the quality of the display can beprevented.

In this embodiment, since the end portions of the light shielding film 9reach the boundary region of the adjacent pixel region 3, the lightshielding film 9 may be formed as an extending portion from anotherlight shielding film 90 or light shielding wiring line passing throughthis boundary region.

As for the arrangement comprising the reflective display region 31 andtransmissive display region 32, any structure may be selected out of astructure in which the reflective display region 31 is wider than thetransmissive display region 32, a structure in which the reflectivedisplay region 31 is narrower than the transmissive display region 32,and a structure in which the reflective display region 31 and thetransmissive display region 32 are equal in area.

Third Embodiment

FIGS. 3A to 3C are schematic views showing a single pixel region of aplurality of pixel regions formed into a matrix shape in a liquidcrystal device of this embodiment, where FIG. 3A is a plan view thereof,and FIGS. 3B and 3C are representations of the A-A′ section and the B-B′section thereof, respectively.

As in the case of the first embodiment, the pixel region shown in FIGS.3A to 3C shows the portion of an active matrix type liquid crystaldevice that is common to cases where either TFDs or TFTs are used asnon-linear elements for pixel switching. The liquid crystal device 1illustrated here also comprises a transparent first substrate 10 withfirst transparent electrodes 11 formed on the surface thereof; atransparent second substrate 20 with second transparent electrodesformed on its surface side opposed to the first electrodes 11; and aliquid crystal layer 50 including a TN mode liquid crystal held betweenthe first substrate 10 and the second substrate 20. The regions wherethe first transparent electrodes 11 and the second transparentelectrodes 21 are mutually opposed constitute the pixel regions 3, whichdirectly contribute to display. The pixel regions 3 are each in a statesurrounded by the light shielding films 90 or light shielding wiringlines in a plan view.

On the first substrate 10, light reflecting layers 4 each constituting areflective display region 31 are each formed of an aluminum film or asilver alloy film, in the rectangular pixel region 3 where the firsttransparent electrode 11 and the second transparent electrode 21 aremutually opposed, and a rectangular opening 40 is formed at the portioncorresponding to a corner of each of the light reflecting layers 4. As aresult, in each the pixel regions 3, the region where the lightreflecting layer 4 is formed constitutes the reflective display region31, while the region corresponding to the opening 40 constitutes therectangular transmissive display region 32 where the light reflectinglayer 4 is not formed. Here, two sides of the transmissive displayregion 32 is superimposed on two sides of the pixel region 3.

Polarizers 41 and 42 are disposed on the outer surfaces of the first andsecond substrate 10 and 20, respectively, and a backlight device 7 isopposed to the polarizer 41 side. Also, on the first substrate 10, areflective display color filter 81 and a transmissive display colorfilter 82 are formed in each of the reflective display regions 31 andeach of the transmissive display regions 32, respectively, therebyallowing color display.

Also, in the first substrate 10, on the lower layer side of the firsttransparent electrode 11, and on the upper layer side of the lightreflecting layer 4, there are provided layer-thickness adjusting layers6 each of which comprises a photoresist and in each of which a regioncorresponding to the transmissive display region 32 constitutes anopening 61. Therefore, in the transmissive display regions 32, since thelayer thickness d of the liquid crystal layer 5 is larger than in thereflective display region 31 by the layer thickness of thelayer-thickness adjusting layer 6, the retardation Δn·d is optimized forboth the transmissive display light and the reflective display light.

In each of the layer-thickness adjusting layers 6, an upwardly inclinedsurface 60 is formed in the boundary region of the reflective displayregion 31 and the transmissive display region 32 so as to have a widthof 8 μm. Accordingly, in this embodiment, on the first substrate 10,light shielding films 9 are each formed in an L-shape in a plan view soas to be superimposed over the entire boundary region of the reflectivedisplay region 31 and the transmissive display region 32. Each of thelight shielding films 9 has a width of 9 μm, and is formed so that theinclined surface 60 is included in the light shielding film 9 in a planview. More specifically, in this embodiment, each of the light shieldingfilm 9 comprising a light shielding metallic film such as a chrome film,is formed into an L-shape along the two sides except the region that issuperimposed on two sides of the pixel region 3, out of the four sidesof the rectangular transmissive display region 32, in a manner such thatone portion of the light shielding film 9 covers the edge portion of thelight reflecting layer 4.

Accordingly, in this embodiment, since each of the light shielding films9 is formed so as to be superimposed over the entire boundary region ofthe reflective display region 31 and the transmissive display region 32as in the case of the first embodiment, it is possible to prevent amalfunction such as a light leakage in the boundary region of thereflective display region 31 and the transmissive display region 32,during black display. Thus, this embodiment produces the same effect asthat of the first embodiment.

As the forming region of the light shielding film 9 becomes wider, thequantity of light, which contributes to display, decreases, and thedisplay tends to be darker. However, in this embodiment, the lightshielding film 9 is formed in an L-shape in a plan view, and the lightshielding film 9 is not formed at the portion corresponding to the twosides of the transmissive display region 32. Consequently, because thetotal length of the light shielding film 9 is short, the reduction inthe amount of light contributed to display can be accordingly kept to aminimum. In this case, since light shielding films 90 and lightshielding wiring lines are, generally speaking, formed in the boundaryregions of adjacent pixel regions, the part of the periphery of thetransmissive display region 32 that are covered by these light shieldingfilms 90 do not of course contribute to display. Hence, even if thereare disturbances in the retardation or in the alignment of liquidcrystal in these portions, the deterioration of the quality of thedisplay can be prevented.

In this embodiment, since the end portions of the light shielding film 9reach the boundary region of the adjacent pixel region 3, the lightshielding film 9 may be formed as an extending portion of another lightshielding film 90 or light shielding wiring line passing through thisboundary region.

As for the arrangement comprising the reflective display region 31 andtransmissive display region 32, any structure may be selected out of astructure in which the reflective display region 31 is wider than thetransmissive display region 32, a structure in which the reflectivedisplay region 31 is narrower than the transmissive display region 32,and a structure in which the reflective display region 31 and thetransmissive display region 32 are equal in area.

Fourth Embodiment

FIGS. 4A and 4B are schematic views showing a single pixel region of aplurality of pixel regions formed into a matrix shape in a liquidcrystal device of this embodiment, where FIG. 4A is a plan view thereof,and FIG. 4B is a representation of the B-B′ section thereof.

As in the case of the first embodiment, the pixel region shown in FIGS.4A and 4B shows the portion of an active matrix type liquid crystaldevice that is common to cases where either TFDs or TFTs are used asnon-linear elements for pixel switching. The liquid crystal device 1illustrated here also comprises a transparent first substrate 10 whichis constituted of quartz, glass or the like, and on the surface of whichfirst transparent electrodes 11 each constituted of an ITO film or thelike is formed; a transparent second substrate 20 which is constitutedof quartz, glass or the like, and on which second transparent electrodeseach constituted of an ITO film or the like, is formed on the surfaceside opposed to the first electrodes 11; and a liquid crystal layer 50including a TN type liquid crystal held between the first substrate 10and the second substrate 20. The regions where the first transparentelectrodes 11 and the second transparent electrodes 21 are mutuallyopposed constitute the pixel regions 3, which directly contribute todisplay. The pixel regions 3 are each in a state surrounded by the lightshielding films 90 or light shielding wiring lines in a plan view.

On the first substrate 10, light reflecting layers 4 each constituting areflective display region 31 are each formed of an aluminum film or asilver alloy film, in the rectangular pixel region 3 where the firsttransparent electrode 11 and the second transparent electrode 21 aremutually opposed, while a region equivalent to about a half of each ofthe pixel regions 3 constitutes a rectangular opening 40 where the lightreflecting layer 4 is not formed. As a result, in each of the pixelregion 3, the region where the light reflecting layer 4 is formedconstitutes the reflective display region 31, while the regioncorresponding to the opening 40 constitutes the rectangular transmissivedisplay region 32 where the light reflecting layer 4 is not formed.Here, three sides of the transmissive display region 32 is superimposedon three sides of the pixel region 3.

Polarizers 41 and 42 are disposed on the outer surfaces of the first andsecond substrate 10 and 20, respectively, and a backlight device 7 isopposed to the polarizer 41 side. Also, on the first substrate 10, areflective display color filter 81 and a transmissive display colorfilter 82 are formed in each of the reflective display regions 31 andeach of the transmissive display regions 32, respectively, therebyallowing color display.

Also, in the first substrate 10, on the lower layer side of the firsttransparent electrode 11, and on the upper layer side of the lightreflecting layer 4, there are provided layer-thickness adjusting layers6 each of which comprises a photoresist and in which a regioncorresponding to the transmissive display region 32 constitutes anopening 61. Therefore, in the transmissive display region 32, since thelayer thickness d of the liquid crystal layer 5 is larger than in thereflective display region 31 by the layer thickness of thelayer-thickness adjusting layer 6, the retardation Δn·d is optimized forboth the transmissive display light and the reflective display light.

In each of the layer-thickness adjusting layers 6, an upwardly inclinedsurface 60 is formed in the boundary region of the reflective displayregion 31 and the transmissive display region 32 so as to have a widthof 8 μm. Accordingly, in this embodiment, on the first substrate 10,light shielding films 9 are each formed in line so as to be superimposedover the entire boundary region of the reflective display region 31 andthe transmissive display region 32. Each of the light shielding film 9has a width of 9 μm, and is formed so that the inclined surface 60 isincluded in the light shielding film 9 in a plan view. Morespecifically, in this embodiment, light shielding films 9 eachcomprising a light shielding metallic film such as a chrome film, areeach formed in line along the one side except the region that issuperimposed on three sides of the pixel region 3, out of the four sidesof the rectangular transmissive display region 32, in a manner such thatone portion of the light shielding film 9 covers the edge portion of thelight reflecting layer 4.

Accordingly, in this embodiment, since each of the light shielding films9 is formed so as to be superimposed over the entire boundary region ofthe reflective display region 31 and the transmissive display region 32as in the case of the first embodiment, it is possible to prevent amalfunction such as a light leakage in the boundary region of thereflective display region 31 and the transmissive display region 32,during black display. Thus, this embodiment produces the same effect asthat of the first embodiment.

As the forming region of the light shielding film 9 becomes wider, thequantity of light, which contributes to display, decreases, and thedisplay trends to be darker. However, in this embodiment, the lightshielding film 9 is formed in line, and the light shielding film 9 isnot formed at the portion corresponding to the three sides of thetransmissive display region 32 out of the four sides of the transmissivedisplay region 32. Consequently, because the total length of the lightshielding film 9 is short, the reduction in the amount of lightcontributed to the display can accordingly be kept to a minimum. In thiscase, since light shielding films 90 and the light shielding wiringlines are, generally speaking, formed in the boundary regions ofadjacent pixel regions 3, the part of the periphery of the transmissivedisplay regions 32 that are covered by these light shielding films 90 donot of course contribute to display. Hence, even if there aredisturbances in the retardation or in the alignment of liquid crystal inthese portions, the deterioration of the quality of the display can beprevented.

In this embodiment, since the end portions of the light shielding film 9reach the boundary region of the adjacent pixel region 3, the lightshielding film 9 may be formed as an extending portion of another lightshielding film 90 or light shielding wiring line passing through thisboundary region.

As for the arrangement comprising the reflective display region 31 andtransmissive display region 32, any structure may be selected out of astructure in which the reflective display region 31 is wider than thetransmissive display region 32, a structure in which the reflectivedisplay region 31 is narrower than the transmissive display region 32,and a structure in which the reflective display region 31 and thetransmissive display region 32 are equal in area.

Fifth Embodiment

The liquid crystal device of this embodiment is one in which the layoutof the light shielding film 9 according to the first embodiment has beenmodified. Since the plan view of the pixel region of this embodiment isthe same as FIG. 1A, FIG. 1A is used also in this embodiment. Here, onlyan A-A′ sectional view of this embodiment is illustrated in FIG. 5. TheB-B′ sectional view thereof is omitted from illustration since it is thesame as FIG. 5. As in the case of the first embodiment, the pixel regionshown in FIG. 5 shows the portion of an active matrix type liquidcrystal device that is common to cases where either TFDs or TFTs areused as non-linear elements for pixel switching.

The liquid crystal device 1 illustrated here also comprises atransparent first substrate 10 with first transparent electrodes 11formed on the surface thereof; a transparent second substrate 20 withsecond transparent electrodes formed on its surface side opposed to thefirst electrodes 11; and a liquid crystal layer 50 including a TN modeliquid crystal held between the first substrate 10 and the secondsubstrate 20. The regions where the first transparent electrodes 11 andthe second transparent electrodes 21 are mutually opposed constitute thepixel regions 3, which directly contribute to display. The pixel regions3 are each in a state surrounded by the light shielding films 90 orlight shielding wiring lines in a plan view. On the first substrate 10,rectangular light reflecting layers 4 each constituting a reflectivedisplay region 31 are each formed of an aluminum film or a silver alloyfilm, in the rectangular pixel region 3 where the first transparentelectrode 11 and the second transparent electrode 21 are opposed, and arectangular opening 40 is formed at the center of each of the lightreflecting layers 4. As a result, in each of the pixel regions 3, theregion where the light reflecting layers 4 is formed constitutes thereflective display region 31, while the region corresponding to theopening 40 constitutes an insular and rectangular transmissive displayregion 32 where the light reflecting layer 4 is not formed.

Polarizers 41 and 42 are disposed on the outer surfaces of the first andsecond substrate 10 and 20, respectively, and a backlight device 7 isopposed to the polarizer 41 side. Also, on the first substrate 10, areflective display color filter 81 and a transmissive display colorfilter 82 are formed in each of the reflective display regions 31 andeach of the transmissive display regions 32, respectively, therebyallowing color display. In this embodiment also, on the first substrate10, layer-thickness adjusting layers 6 are formed, each of whichcomprises a photoresist and in which a region corresponding to thetransmissive display region 32 constitutes an opening on the lower layerside of the first transparent electrode 11, and on the upper layer sideof the light reflecting layer 4. Therefore, in the transmissive displayregion 32, since the layer thickness d of the liquid crystal layer 5 islarger than in the reflective display region 31 by the layer thicknessof the layer-thickness adjusting layer 6, the retardation Δn·d isoptimized for both the transmissive display light and the reflectivedisplay light.

In each of the layer-thickness adjusting layers 6, an upwardly inclinedsurface 60 is formed in the boundary region of the reflective displayregion 31 and the transmissive display region 32 so as to have a widthof 8 μm. Accordingly, in this embodiment, on the second substrate 20,light shielding films 9 are each formed in a rectangular frame shape soas to be superimposed over the entire boundary region of the reflectivedisplay region 31 and the transmissive display region 32 in a plan view.Each of the light shielding film 9 has a width of 9 μm, and is formed sothat the inclined surface 60 is included in the light shielding film 9in a plan view.

Accordingly, in this embodiment, since each of the light shielding films9 is formed so as to be superimposed over the entire boundary region ofthe reflective display region 31 and the transmissive display region 32as in the case of the first embodiment, it is possible to prevent amalfunction such as a light leakage in the boundary region of thereflective display region 31 and the transmissive display region 32,during black display. Thus, this embodiment produces the same effect asthat of the first embodiment.

Sixth Embodiment

The liquid crystal device of this embodiment is a modification in whichthe structure of pixel electrodes and the arrangement of color filtersformed on the first substrate 10 of the liquid crystal device accordingto the first embodiment have been modified. Since the plan view of thepixel region of this embodiment is the same as FIG. 1A, FIG. 1A is alsoused in this embodiment. Here, only an A-A′ sectional view of thisembodiment is illustrated in FIG. 6. The B-B′ sectional view thereof isomitted from illustration since it is the same as FIG. 6. As in the caseof the first embodiment, the pixel region shown in FIG. 6 shows theportion of an active matrix type liquid crystal device that is common tocases where either TFDs or TFTs are used as non-linear elements forpixel switching.

The liquid crystal device 1 illustrated here comprises a transparentfirst substrate 10 with pixel electrodes 11T and 11R formed on thesurface thereof; a transparent second substrate 20 with secondtransparent electrodes 21 formed on its surface side opposed to thefirst substrate 10; and a liquid crystal layer 50 including a TN modeliquid crystal held between the first substrate 10 and the secondsubstrate 20. The regions where the pixel electrodes 11T and 11R and thesecond transparent electrodes 21 are mutually opposed constitute thepixel regions 3, which directly contribute to display. The pixel regions3 are each in a state surrounded by the light shielding films 90 orlight shielding wiring lines in a plan view, and are each disposed inthe opening 40.

Here, the pixel electrodes formed on the first substrate 10 compriselight reflecting electrodes 11R each constituted of an aluminum film ora silver alloy film and first transparent electrodes 11T eachconstituted of an ITO film or the like. The light reflecting electrodes11R are each formed in a rectangular frame shape along the outerperiphery of the pixel region 3, and the first transparent electrodes11T are each disposed inside the opening 40 at the central portion.Namely, in this embodiment, the arrangement is made such that each ofthe light reflecting layers also serves as a pixel electrode. As aresult, in each of the pixel region 3, the region where the lightreflecting electrode 11R is formed constitutes the reflective displayregion 31, while the region corresponding to the opening 40 constitutesan insular and rectangular transmissive display region 32 where thelight reflecting electrode 11R is not formed.

Polarizers 41 and 42 are disposed on the outer surfaces of the first andsecond substrate 10 and 20, respectively, and a backlight device 7 isopposed to the polarizer 41 side. Also, in this embodiment, on thesecond substrate 20, a reflective display color filter 81 and atransmissive display color filter 82 are formed in each of thereflective display regions 31 and each of the transmissive displayregions 32, respectively, thereby allowing color display. On these colorfilters, the above-described second transparent electrodes 21 areformed.

In this embodiment, on the lower layer side of the pixel electrodes 11Rand 11T, there are provided layer-thickness adjusting layers 6 each ofwhich comprises a photoresist and in each of which a regioncorresponding to the transmissive display region 32 constitutes anopening 61. Therefore, in the transmissive display region 32, since thelayer thickness d of the liquid crystal layer 5 is larger than in thereflective display region 31 by the layer thickness of thelayer-thickness adjusting layer 6, the retardation Δn·d is optimized forboth the transmissive display light and the reflective display light.

In each of the layer-thickness adjusting layers 6, an upwardly inclinedsurface 60 is formed in the boundary region of the reflective displayregion 31 and the transmissive display region 32 so as to have a widthof 8 μm. Accordingly, in this embodiment, on the first substrate 10,each of the light shielding films 9 is formed in a rectangular frameshape so as to be superimposed over the entire boundary region of thereflective display region 31 and the transmissive display region 32 in aplan view. Each of the light shielding film 9 has a width of 9 μm, andis formed so that the inclined surface 60 is included in the lightshielding film 9 in a plan view.

Accordingly, in this embodiment, since each of the light shielding films9 is formed so as to be superimposed over the entire boundary region ofthe reflective display region 31 and the transmissive display region 32as in the case of the first embodiment, it is possible to prevent amalfunction such as a light leakage in the boundary region of thereflective display region 31 and the transmissive display region 32,during black display. Thus, this embodiment produces the same effect asthat of the first embodiment.

Meanwhile, in the above-described sixth embodiment, while the lightshielding film 9 are each formed on the first substrate 10 side, thelight shielding film 9 may be each formed on the second substrate 20side as in the case of the fifth embodiment. In this case also, the sameeffect can be exerted.

Seventh Embodiment

The liquid crystal device of this embodiment is a modification in whichthe arrangement of the layer-thickness adjusting layers 6 according tothe first embodiment has been modified. Since the plan view of the pixelregion of this embodiment is the same as FIG. 1A, FIG. 1A is also usedin this embodiment. Here, only an A-A′ sectional view of this embodimentis illustrated in FIG. 7. The B-B′ sectional view thereof is omittedfrom illustration since it is the same as FIG. 7. As in the case of thefirst embodiment, the pixel region shown in FIG. 7 shows the portion ofan active matrix type liquid crystal device that is common to caseswhere either TFDs or TFTs are used as non-linear elements for pixelswitching.

The liquid crystal device 1 illustrated here also comprises atransparent first substrate 10 with first transparent electrodes 11formed on the surface thereof; a transparent second substrate 20 withsecond transparent electrodes formed on its surface side opposed to thefirst electrodes 11; and a liquid crystal layer 50 including a TN modeliquid crystal held between the first substrate 10 and the secondsubstrate 20. The regions where the first transparent electrodes 11 andthe second transparent electrodes 21 are mutually opposed constitute thepixel regions 3, which directly contribute to play. The pixel regions 3are each in a state surrounded by the light shielding films 90 or lightshielding wiring lines in a plan view. On the first substrate 10,rectangular light reflecting layers 4 each constituting a reflectivedisplay region 31 are each formed of an aluminum film or a silver alloyfilm, in the rectangular pixel region 3 where the first transparentelectrode 11 and the second transparent electrode 21 are opposed, and arectangular opening 40 is formed at the center of each of the lightreflecting layers 4. As a result, in each of the pixel region 3, theregion where the light reflecting layer 4 is formed constitutes thereflective display region 31, while the region corresponding to theopening 40 constitutes an insular and rectangular transmissive displayregion 32 where the light reflecting layer 4 is not formed.

Polarizers 41 and 42 are disposed on the outer surfaces of the first andsecond substrate 10 and 20, respectively, and a backlight device 7 isopposed to the polarizer 41 side. Also, on the first substrate 10, areflective display color filter 81 and a transmissive display colorfilter 82 are formed in the each of the reflective display regions 31and each of the transmissive display regions 32, respectively, therebyallowing color display.

In this embodiment, in the second substrate 20, on the lower layer sideof the second transparent electrode 21, there are providedlayer-thickness adjusting layers 6 each of which comprises a photoresistand in each of which a region corresponding to the transmissive displayregion 32 constitutes an opening 61. Therefore, in the transmissivedisplay regions 32, since the layer thickness d of the liquid crystallayer 5 is larger than in the reflective display region 31 by the layerthickness of the layer-thickness adjusting layer 6, the retardation Δn·dis optimized for both the transmissive display light and the reflectivedisplay light.

Here, in each of the layer-thickness adjusting layers 6, an upwardlyinclined surface 60 is formed in the boundary region of the reflectivedisplay region 31 and the transmissive display region 32 so as to have awidth of 8 μm. Accordingly, in this embodiment, on the first substrate10, light shielding films 9 are each formed into a rectangular frameshape so as to be superimposed over the entire boundary region of thereflective display region 31 and the transmissive display region 32.Each of the light shielding films 9 has a width of 9 μm, and is formedso that the inclined surface 60 is included in the light shielding film9 in a plan view.

Accordingly, in this embodiment, since each of the light shielding films9 is formed so as to be superimposed over the entire boundary region ofthe reflective display region 31 and the transmissive display region 32as in the case of the first embodiment, it is possible to prevent amalfunction such as a light leakage in the boundary region of thereflective display region 31 and the transmissive display region 32,during black display. Thus, this embodiment produces the same effect asthat of the first embodiment.

Meanwhile, in the above-described seventh embodiment, while the lightshielding films 9 are each formed on the first substrate 10 side, thelight shielding films 9 may be each formed on the second substrate 20side as in the case of the fifth embodiment. In this case also, the sameeffect can be exerted.

Eighth Embodiment

The liquid crystal device of this embodiment is a modification in whichthe arrangement of the light shielding films 9 and the layer-thicknessadjusting layers 6 according to the sixth embodiment has been modified.Since the plan view of the pixel region of this embodiment is the sameas FIG. 1A, FIG. 1A is also used in this embodiment. Here, only an A-A′sectional view of this embodiment is illustrated in FIG. 8. The B-B′sectional view thereof is omitted from illustration since it is the sameas FIG. 8. As in the case of the first embodiment, the pixel regionshown in FIG. 8, shows the portion of an active matrix type liquidcrystal device that is common to cases where either TFDs or TFTs areused as non-linear elements for pixel switching.

The liquid crystal device 1 illustrated here comprises a transparentfirst substrate 10 with pixel electrodes 11T and 11R formed on thesurface thereof; a transparent second substrate 20 with secondtransparent electrodes formed on its surface side opposed to the firstsubstrate 10; and a liquid crystal layer 50 including a TN mode liquidcrystal held between the first substrate 10 and the second substrate 20.The regions where the pixel electrodes 11T and 11R and the secondtransparent electrodes 21 are mutually opposed constitute the pixelregions 3, which directly contribute to display. The pixel regions 3 areeach in a state surrounded by the light shielding films 90 or lightshielding wiring lines in a plan view, and are each disposed in theopening 40.

Here, the pixel electrodes formed on the first substrate 10 compriselight reflecting electrodes 11R each constituted of an aluminum film ora silver alloy film and a first transparent electrodes 11T eachconstituted of an ITO film or the like. The light reflecting electrodes11R are each formed in a rectangular frame shape along the outerperiphery of the pixel region 3, and the first transparent electrodes11T are each disposed inside the opening 40 at the central portion. Inthis embodiment, the arrangement is made such that each of the lightreflecting layers also serves as a pixel electrode. As a result, in eachof the pixel regions 3, the region where the light reflecting electrode11R is formed constitutes the reflective display region 31, while theregion corresponding to the opening 40 constitutes an insular andrectangular transmissive display region 32 where the light reflectingelectrode 11R is not formed.

Polarizers 41 and 42 are disposed on the outer surfaces of the first andsecond substrate 10 and 20, respectively, and a backlight device 7 isopposed to the polarizer 41 side. Also, in this embodiment, on thesecond substrate 20, a reflective display color filter 81 and atransmissive display color filter 82 are formed in each of thereflective display regions 31 and each of the transmissive displayregions 32, respectively, thereby allowing color display.

In this embodiment, in the second substrate 20, on the lower layer sideof the second transparent electrode 21, and on the upper layer side ofthe color filter 81 and 82, there are provided layer-thickness adjustinglayers 6 each of which comprises a photoresist and in each of which aregion corresponding to the transmissive display region 32 constitutesan opening 61. Therefore, in the transmissive display region 32, sincethe layer thickness d of the liquid crystal layer 5 is larger than inthe reflective display region 31 by the layer thickness of thelayer-thickness adjusting layer 6, the retardation Δn·d is optimized forboth the transmissive display light and the reflective display light.

Here, in each of the layer-thickness adjusting layers 6, an upwardlyinclined surface 60 is formed in the boundary region of the reflectivedisplay region 31 and the transmissive display region 32 so as to have awidth of 8 μm. Accordingly, in this embodiment, on the second substrate20, light shielding films 9 are each formed into a rectangular shape soas to be superimposed over the entire boundary region of the reflectivedisplay region 31 and the transmissive display region 32. Each of thelight shielding film 9 has a width of 9 μm, and is formed so that theinclined surface 60 is included in the light shielding film 9 in a planview.

Accordingly, in this embodiment, since each of the light shielding films9 is formed so as to be superimposed over the entire boundary region ofthe reflective display region 31 and the transmissive display region 32as in the case of the first embodiment, it is possible to prevent amalfunction such as a light leakage in the boundary region of thereflective display region 31 and the transmissive display region 32,during black display. Thus, this embodiment produces the same effect asthat of the first embodiment.

Meanwhile, in the above-described seventh embodiment, while the lightshielding film 9 is formed on the first substrate 10 side, the lightshielding film 9 may be formed on the second substrate 20 side as in thecase of the fifth embodiment. In this case also, the same effect can beexerted.

Ninth Embodiment

Next, description will be made of the structure of a TFD active matrixtype liquid crystal device in which a structure according to any one ofthe first to eighth embodiments is used.

FIG. 9 is a block diagram showing the electrical configuration of theliquid crystal device. FIG. 10 is an exploded perspective view showingthe structure of this liquid crystal device. FIG. 11 is a plan viewcorresponding to a single pixel on an element substrate out of a pair ofsubstrates sandwiching the liquid crystal therebetween in the liquidcrystal device. FIG. 12A is a sectional view taken along the lineIII-III′ in FIG. 11, and FIG. 12B is a perspective view illustrating aTFD element formed in each pixel.

In the liquid crystal device 100 shown in FIG. 9, scanning lines 151 asa plurality of wiring lines are formed in the row direction(X-direction), and a plurality of data lines are formed in the columndirection (Y-direction). A pixel 153 is formed at the positioncorresponding to each of the intersections between the scanning lines151 and the data lines 152. In each of the pixels 153, a liquid crystallayer 154 and a pixel switching TFD element (non-linear element) 156 areconnected in series. Each of the scanning lines is driven by a scanningline driving circuit 157, and each of the data lines is driven by a dataline driving circuit 158.

As shown in FIG. 10, in the active matrix type liquid crystal device 100with this arrangement, on an element substrate 120 out of a pair oftransparent substrates holding a liquid crystal 106, a plurality ofscanning lines extends, and each pixel electrode 166 is electricallyconnected to one of the scanning lines 151 through one of the TFDelement 156. On the other hand, on an opposing substrate 110, pluralcolumns of band-shaped data lines 152 that extend in the directionintersecting the scanning line 151 on the element substrate 120, areeach formed of an ITO film. Light shielding films 159 referred to as“black stripes” are formed between data lines. Each of the pixelelectrodes 166, therefore, is in a state surrounded by light shieldingfilms 159 and scanning lines 151 in a plan view.

An ordinary TN mode crystal liquid 106 is used as a liquid crystal 106.Since this type of liquid crystal 106 performs an optical modulation bychanging the polarization direction of light, polarizers 108 and 109 aredisposed so as to be overlaid on the outer surfaces of the elementsubstrate 120 and the opposing substrate 110, respectively. Also, abacklight device 103 is opposed to the polarizer 108 side.

In the example shown here, the scanning lines 151 have been formed onthe element substrate 120, and the data lines 152 have been formed onthe opposing substrate 110. Alternatively, however, the scanning lines151 may be formed on the opposing substrate 110, and the data lines 152may be formed on the element substrate 110.

As shown in FIG. 11 and FIGS. 12A and 12B, the TFD element 156 isformed, for example, as a so-called “back-to-back” structure by two TFDelement components that comprise a first TFD element 156 a and a secondTFD element 156 b, and that are formed on a foundation layer 161deposited on the surface of the element substrate 120. Thereby, in theTFD element 156, the non-linearity between current and voltage issymmetrized in both positive and negative directions. The foundationlayer 161 comprises, for example, tantalum oxide (Ta2O5) with athickness of about 50 to 200 nm.

The first TFD element 156 a and the second TFD element 156 b both have afirst metallic film 162, an insulating film 163 formed on the firstmetallic film 162, and have respective second metallic films 164 a and164 b formed in a spaced apart manner on the surface of the insulatingfilm 163. The first metallic film 162 is formed of, for example, asingle substance film of Ta (tantalum) with a thickness of about 100 to500 nm, or a Ta alloy film such as a Ta—W (tantalum-tungsten) alloyfilm. The insulating film 163 is constituted of, for example, tantalumoxide (Ta2O5) with a thickness of 10 to 35 nm formed by oxidizing thesurface of the first metallic film 62 by an anodic oxidation method.

The second metallic films 164 a and 164 b are each formed of a lightshielding metallic film, such as a Cr (chrome) film with a thickness ofabout 50 to 300 nm. The second metallic film 164 a constitutes ascanning line 151 as it is, while the second metallic film 164 b isconnected to the pixel electrode 166, which comprises an ITO film or thelike.

In the liquid crystal device 100 arranged in this way, each region wherethe pixel electrode 166 and the data line 152 are mutually opposedconstitutes the pixel region 3, which has been described in the first toeighth embodiments. Therefore, the element substrate 120, the opposingsubstrate 110, the pixel electrode 166, and the data line 152 correspondto the first substrate 10, the second substrate 20, the first electrode11, and the second electrode 21 in the first to eighth embodiments,respectively. Thus, it proves that, on the lower layer side of the pixelelectrode 166, the light reflecting layer 4, the light shielding film 9,the reflective display color filter 81, the transmissive display colorfilter 82, and the layer-thickness adjusting layer 6, which have beendescribed with reference to FIGS. 1 to 4, are formed.

Here, when the arrangement described in the fourth embodiment is to beapplied to the liquid crystal device 100, each of the pixel electrodes166 is formed so as to straddle the scanning line 151, and one ofopposite sides of the scanning line 151 is used as a reflective displayregion 31, while the other side thereof is used as a transmissivedisplay region 32. Thereby, the scanning line 151 is formed along theboundary region of the reflective display region 31 and the transmissivedisplay region 32. Thus, the scanning line 151 can be utilized as thelight shielding film shown in FIG. 4.

Also, in the liquid crystal device 100, the element substrate 120, theopposing substrate 110, the pixel electrode 166, and the data line 152may be used as the second substrate 20, the first substrate 10, thesecond electrode 21, and the first electrode 11 in the first to eighthembodiments, respectively. In this case, it proves that, on the lowerlayer side of the data line 152, the light reflecting layer 4, the lightshielding film 9, the reflective display color filter 81, thetransmissive display color filter 82, and the layer-thickness adjustinglayer 6, which have been described with reference to FIGS. 1 to 4, areformed, and that a backlight device 163 is opposed to the opposingsubstrate 200.

Tenth Embodiment

Next, description will be made of the structure of a TFT active matrixtype liquid crystal device in which a structure according to any one ofthe first to eighth embodiments is used.

FIG. 13 is a plan view showing the TFT active matrix type liquid crystaldevice and the components thereof, as viewed from the opposing substrateside, and FIG. 14 is a representation showing the H-H′ section in FIG.13. FIG. 15 is an equivalent circuit diagram of various elements andwiring lines formed on a plurality of pixels formed into a matrix shapein the image display region in the liquid crystal device.

As shown in FIGS. 13 and 14, in the liquid crystal device 200 of thisembodiment, a TFT array substrate 210 and an opposing substrate 220 arebonded together with a seal material 252, and a liquid crystal 250 as anelectro-optical substance is held in a region (liquid crystal enclosingregion) defined by the seal material 252. Polarizers 288 and 289 aredisposed on the TFT array substrate 210 and the opposing substrate 220,respectively, and a backlight device 290 is opposed to the polarizer 288side.

On the inside area of the forming region of the seal material 252, aperipheral partition 252 comprising a light shielding material isformed. On the outside area of the seal material 252, a data linedriving circuit 301 and mounting terminals 302 are formed along one sideof the TFT array substrate 210, and a scanning line driving circuit 304is formed along the two sides adjacent to the aforementioned one side.Along the remaining one side of the TFT array substrate 210, there isprovided a plurality of wiring lines 305 for interconnecting thescanning line driving circuits 304 provided on the opposite sides of theimage display area 210 a. Furthermore, in some case, a precharge circuitand/or an inspection circuit are provided making use of the space belowthe peripheral partition 253. Also, at least one place in a cornerportion of the opposing substrate 220, an inter-substrate conductivematerial 306 is formed for establishing an electrical conduction betweenthe TFT array substrate 210 and the opposing substrate 220.

Instead of forming the data line driving circuit 301 and the scanningline driving circuits 304 on the TFT array substrate 210, for example, aTAB (Tape Automated Bonding) substrate on which LSIs for drive aremounted, may be electrically and mechanically connected to a group ofterminals formed on the periphery of the TFT array substrate 210 throughan anisotropic conductive film. Meanwhile, the liquid crystal 50 is usedin the TN mode also in the liquid crystal device 200 of this embodiment.

As shown in FIG. 15, in the image display region 210 a of the liquidcrystal device 200 with this arrangement, a plurality of pixels 200 a isformed into a matrix shape. In each of these pixels 200 a, a pixelelectrode 209 a and a pixel-switching TFT 230 for driving the pixelelectrode are formed, and a data line 206 a for supplying pixel signalsS1, S2 . . . , Sn is electrically connected to the source of the TFT230. The pixel signals S1, S2 . . . , Sn written into the data lines 206a may be line-sequentially supplied in this order, or alternatively theymay be supplied for every group of the plurality of mutually adjacentdata lines 206 a. Also, scanning lines 203 a are electrically connectedto the gate of each of the TFTs 230, and at a predetermined timing,scanning signals G1, G2 . . . , Gm in the form of pulses areline-sequentially applied to the scanning lines 203 a in this order. Thepixel electrodes 209 a are electrically connected to the drain of eachof the TFTs 230 a, and each of the TFTs 230 as a switching element iskept in its ON state during a definite time period so as to write pixelsignals S1, S2 . . . , Sn supplied from the data line 206 a into eachpixel at a predetermined timing. In this manner, the pixel signals S1,S2 . . . , Sn of a predetermined level, which have been written to theliquid crystal via the pixel electrode 209 a, are held for a definitetime period between the pixel electrodes 209 a and an opposing electrode221 formed on the opposing substrate 220 shown in FIG. 14.

The liquid crystal 250 modulates light by the variation in theorientation and the order of the molecular aggregation thereof accordingto the level of an applied voltage, thereby making it possible toprovide grayshade display. In the normally white mode, the amount ofincident light passing through the liquid crystal 250 portion decreasesaccording to the level of an applied voltage, whereas in the normallyblack mode, the amount of incident light passing through the liquidcrystal 250 portion increases according to the level of an appliedvoltage. Consequently, light having contrast according to the pixelsignals S1, S2 . . . , Sn is emitted from the liquid crystal device 200,as a whole.

In order to inhibit the held pixel signals S1, S2 . . . , Sn fromleaking, a storage capacitor 260 may be added thereto in parallel with aliquid crystal capacitor formed between the pixel electrode 209 a andthe opposing electrode. For example, the voltage of the pixel electrode209 a is held by the storage capacitor 260 for a time period longer bythree orders of magnitude than the time period during which a sourcevoltage is applied to the pixel electrode 209 a. This improves theelectric charge holding characteristic, thereby making it possible toachieve a liquid crystal device 200 having a high contrast ratio.Meanwhile, with regard to the formation of the storage capacitor 260, asillustrated in FIG. 15, the storage capacitor 260 may be formed betweenthe pixel electrode 209 a and a capacitor line 203 b, which is a wiringline for forming the storage capacitor 260, or alternatively it can beformed between the pixel electrode 209 a and a pre-stage scanning line203 a.

FIG. 16A is a plan view illustrating the configuration of pixels formedon a TFT array substrate to which an arrangement according to any one ofthe embodiments 1 to 3, or 5 to 8 has been applied, in the liquidcrystal device shown in FIG. 13, and FIG. 16B is a plan viewillustrating the configuration of pixels formed on a TFT array substrateto which the arrangement according to the embodiment 4 has been applied.FIG. 17 is a sectional view showing some of the pixels of the liquidcrystal device according to this embodiment, the sectional view beingobtained by cutting them at the position corresponding to the line C-C′shown in FIGS. 16A and 16B.

As shown in FIG. 16A, in the liquid crystal device shown in FIG. 13,when a structure according to any one of the embodiments 1 to 3, or 5 to8 has been applied, a plurality of pixel electrodes 209 a eachcomprising a transparent ITO film is formed into a matrix shape, and apixel switching TFT 230 is connected to each of the pixel electrodes 209a. Data lines 206 a, scanning lines 203 a, and capacitor lines 203 b areformed along the longitudinal and lateral boundaries of the pixelelectrodes 209 a, and each of the TFTs 230 is connected to the data line206 a and the scanning line 203 a. Specifically, each of the data lines206 a is electrically connected to a high-concentration source region201 d of the TFT 230 through a contact hole, and each of the pixelelectrodes 209 a is electrically connected to a high-concentration drainregion 201 e of the TFT 230 through a contact hole. Each of scanninglines 203 a extends so as to be opposed to a channel region 201′ of theTFT 230. Here, the storage capacitors 260 each have a structure in whichthe extending portion 201 f of the semiconductor film 201 for formingthe pixel switching TFT 230 is used as a lower electrode after havingbeen made conductive, and in which the capacitor line 203 b in the samelayer as the scanning line 203 a is opposed to the aforementioned lowerelectrode 241, as an upper electrode.

The capacitor line 203 b comprises a main line portion 203 b ′ thatextends along the scanning line 203 a in the vicinity thereof, and aprojecting portion 203 b″ that projects from the main line portion 203′along the data line 206 a.

However, when the arrangement according to the fourth embodiment isapplied to the liquid crystal device shown in FIG. 13, the capacitorline 203 a comprises, as shown in FIG. 16B, a main line portion 203 b′that extends along the scanning line 203 a from the substantiallyintermediate position of two adjacent scanning lines 203 a, and aprojecting portion 203 b″ that, after having projected from the mainline portion 203 b′ along the data line 206 a, extends along thescanning line 203 a in the vicinity thereof. In this case, by using oneof opposite sides of the main portion 203′ of the capacitor line 203 bas the reflective region 31, and using the other of the opposite sidesas the transmissive region 32, a capacitor line 203 b is formed alongthe boundary region thereof. The main line portion 203 b′ of thecapacitor line 203B, therefore, can be utilized as the light shieldingfilm 9 shown in FIG. 4.

In the liquid crystal device 200 arranged in this way, an insularsemiconductor film 201 a with a thickness of 50 to 100 nm is formed onthe surface of the TFT array substrate 210. A gate insulating film 202constituted of a silicon oxide film with a thickness of 50 to 150 nm isformed on the surface of the semiconductor film 201. The scanning line203 a with a thickness of 300 to 800 nm runs on the surface of the gateinsulating film 202, as a gate electrode. Out of the semiconductor film201 a, the region that is opposed to the scanning line 203 a with thegate insulating film 202 therebetween, constitutes a channel region 201a′. With respect to this channel region 201 a′, a source region thatincludes a low-concentration source region 201 b and ahigh-concentration source region 201 d is formed on one side, and adrain region that includes a low-concentration drain region 201 c and ahigh-concentration drain region 201 e is formed on the other side.

On the surface side of the pixel switching TFT 230, there are provided afirst inter-layer insulating film 204 constituted of silicon oxide filmwith a thickness of 300 to 800 nm and a second inter-layer insulatingfilm 205 constituted of silicon nitride film with a thickness of 100 to300 nm. A data line 206 a with a thickness of 300 to 800 nm is formed onthe surface of the first interlayer insulating film 204, and iselectrically connected to the high-concentration source region 201 dthrough a contact hole formed in the first interlayer insulating film204.

A pixel electrode 209 a comprising an ITO film is formed on the upperlayer of the second inter-layer insulating film 205. The pixel electrode209 a is electrically connected to the drain electrode 206 b through acontact hole formed in the second inter-layer insulating film 205. Analignment film 212 constituted of a polyimide film is formed on thesurface side of the pixel electrode 209 a. The alignment film 212 is afilm obtained by applying a rubbing treatment to the polyimide film.

The storage capacitor 260 is constituted by opposing the capacitor line203 b in the same layer as the scanning line 203 a as the upperelectrode, to the extending portion 201 f (lower electrode) from thehigh-concentration drain region 201 e, with an insulating film(dielectric film) formed simultaneously with the gate insulating film202 interposed therebetween.

The TFT 230 preferably has an LDD (Lightly Doped Drain) structure asdescribed above. Alternatively, however, the TFT 230 may have an offsetstructure in which impurity ion implantation is not applied to regionscorresponding to the low-concentration source region 201 b and thelow-concentration drain region 201 c. Furthermore, alternatively, theTFT 230 may be a self-alignment type TFT in which impurity ionimplantation is performed at a high concentration with a gate electrode(a portion of the scanning line 203 a) as a mask, and high-concentrationsource and drain areas are formed in a self-alignment manner.

In this embodiment, a single gate structure is adopted in which only onegate electrode (scanning line 203 a) of the TFT 230 is disposed betweenthe high-concentration source region and the high-concentration drainregion. However, two or more gate electrodes may be disposed betweenthese regions. In this case, the same signal should be applied to thesegate electrodes. In this manner, by forming the TFT 230 with dual,triple, or more multiple gates as described above, leaking currents canbe prevented at a channel and the connecting portion between a channeland the source/drain regions, thus reducing currents during power-off.By arranging at least one of these gate electrodes to have the LDDstructure or the offset structure, it is possible to further reduceoff-currents and to form a stable switching element.

As shown in FIG. 17, on the opposing substrate 220, a light shieldingfilm 223 referred to as a “black matrix” or a “black stripe” is formedin the region opposed to the longitudinal and lateral boundary regionsof the pixel electrode 209 a formed on the TFT array substrate 210, andan opposing electrode 221 comprising an ITO film is formed on the upperlayer side of the light shielding film 223. Also, an alignment film 222constituted of a polyimide film is formed on the upper layer side of theopposing electrode 221. This alignment film 222 is a film obtained byapplying a rubbing treatment to the polyimide film.

In the liquid crystal device 200 arranged in this manner, the regionwhere the pixel electrode 209 a and the opposing electrode 221 aremutually opposed, corresponds to the pixel region described in the firstto eighth embodiments. Therefore, the TFT array substrate 210, theopposing substrate 220, the pixel electrode 209 a, and the opposingelectrode 221 correspond to the first substrate 10, the second substrate20, the first electrode 11, and the second electrode 21 in the first toeighth embodiments, respectively. In this case, it proves that, on thelower layer side of the pixel electrode 209 a, there are provided thelight reflecting layer 4, the light shielding film 9, the reflectivedisplay color filter 81, the transmissive display color filter 82, andthe layer-thickness adjusting layer 6, which have been described withreference to FIGS. 1 to 8.

Alternatively, in the liquid crystal device 200, the TFT array substrate210, the opposing substrate 220, the pixel electrode 209 a, and theopposing electrode 221 may be used as the second substrate 20, the firstsubstrate 10, the second electrode 21, and the first electrode 11 in thefirst to eighth embodiments, respectively. In this case, it proves that,on the lower layer side of the opposing electrode 221, there areprovided the light reflecting layer 4, the light shielding film 9, thereflective display color filter 81, the transmissive display colorfilter 82, and the layer-thickness adjusting layer 6, which have beendescribed with reference to FIGS. 1 to 8, are formed, and that abacklight device 290 is opposed to the opposing substrate 200.

Application of Liquid Crystal Device to Electronic Device

The transflective liquid crystal device arranged in this manner can beused as a display for various electronic devices. An example thereofwill be described with reference to FIGS. 18 to 20.

FIG. 18 is a block diagram showing the circuit configuration of anelectronic device in which a liquid crystal device according to thepresent invention is used as a display.

In FIG. 18, the electronic device comprises a display information outputsource 570, a display information processing circuit 571, a power supplycircuit 572, a timing generator 573, and a liquid crystal device 574.The liquid crystal device 574 has a liquid crystal display panel 575 anda drive circuit 576. As the liquid crystal device 574, any one of theliquid crystal devices 1, 100, and 200 to which the present inventionhas been applied, can be used.

The display information output source 570 comprises memories such as aROM (Read Only Memory and a RAM (Random Access Memory), storage unitsincluding various disks, and a synchronization circuit that outputsdigital image signals in synchronization. The display information outputsource 570 supplies the display information processing circuit 571 withdisplay information such as image signals of a predetermined format inresponse to various clock signals produced by the timing generator 573.

The display information processing circuit 571 comprises various knowncircuits such as a serial-parallel conversion circuit, anamplification/polarity reversing circuit, a rotation circuit, a gammacorrection circuit, and a clamp circuit. The display informationprocessing circuit 571 processes display information that has beeninputted, and supplies the generated image signals together with a clocksignal CLK to the drive circuit 576. The power supply circuit 572supplies a predetermined voltage to the individual components.

FIG. 19 show a mobile personal computer as an embodiment of anelectronic device according to the present invention. The illustratedpersonal computer 580 comprises a main body portion 582 equipped with akeyboard 581, and a liquid crystal display unit 583. The liquid crystaldisplay unit 583 is arranged to include any one of the liquid crystaldevices 1, 100, and 200 to which the present invention has been applied.

FIG. 20 shows a portable telephone as another embodiment of anelectronic device according to the present invention. The illustratedportable telephone 590 comprises a plurality of operation buttons 591and a display portion including any one of the liquid crystal devices 1,100, and 200 to which the present invention has been applied.

As is evident from the foregoing, in the transflective liquid crystaldevice according to present invention, light shielding films are eachformed so as to be superimposed over the entire boundary region of thereflective display region and the transmissive display region. As aresult, even when the thickness of each of the layer-thickness adjustinglayers continuously varies in the boundary region of the reflectivedisplay region 31 and the transmissive display region 32, andconsequently the retardation Δn·d continuously varies in this portion,or the alignment of liquid crystal molecules is disturbed, neitherreflective display light nor transmissive display light would be emittedfrom such a region. This prevents a malfunction such as a light leakageduring black display, resulting in an achievement of high-contrast andhigh-quality display.

1. A transflective liquid crystal device comprising: a first substrate;a second substrate opposite the first substrate; a liquid crystal layerbetween the first and second substrates; a light reflecting layerbetween the liquid crystal layer and the first substrate, the lightreflecting layer having edges that define a reflective display region,an edge of the light reflecting layer serving as a boundary regionbetween the reflective display region and a transmissive display region;a layer thickness adjusting layer between the liquid crystal layer andthe first substrate, the layer thickness adjusting layer setting a firstlayer thickness of the liquid crystal layer in the reflective displayregion and a second layer thickness of the liquid crystal layer in thetransmissive display region, the first layer thickness being less thanthe second layer thickness; and a light shielding film that overlaps theboundary region between the reflective display region and thetransmissive display region in plan view.
 2. The transflective liquidcrystal device according to claim 1, wherein the light shielding film isformed on a side of the first substrate.
 3. The transflective liquidcrystal device according to claim 1, wherein the layer-thicknessadjusting layer includes an inclined surface that overlaps the lightshielding film in plan view.
 4. The transflective liquid crystal deviceaccording to claim 1, wherein the light shielding film further comprisesa wiring line.
 5. The transflective liquid crystal device according toclaim 1, wherein the reflective display region and the transmissivedisplay region are individually provided with a color filter.
 6. Thetransflective liquid crystal device according to claim 1, wherein areflective display color filter is formed in the reflective displayregion, and a transmissive display color filter having a higher coloringdegree than the reflective display color filter is formed in thetransmissive display region.
 7. A transflective liquid crystal deviceaccording to claim 1, wherein the reflective display region and thetransmissive display region are substantially equal in area.
 8. Atransflective liquid crystal device comprising: a first substrate; asecond substrate opposite the first substrate; a liquid crystal layerbetween the first and second substrates; a light reflecting layerbetween the liquid crystal layer and the first substrate, the lightreflecting layer defining a reflective display region, at least one edgeof the light reflecting layer defining a boundary region between thereflective display region and a transmissive display region; a layerthickness adjusting layer between the liquid crystal layer and the firstsubstrate, the layer thickness adjusting layer setting a first layerthickness of the liquid crystal layer in the reflective display regionand a second layer thickness of the liquid crystal layer in thetransmissive display region, the first layer thickness being less thanthe second layer thickness; and a light shielding wire that overlaps theboundary region between the reflective display region and thetransmissive display region in plan view.
 9. The transflective liquidcrystal device according to claim 8, wherein the layer-thicknessadjusting layer includes an inclined surface that overlaps the lightshielding wire in plan view.